Intrathoracic desmoid tumor: CT and MRI appearance.

Intrathoracic desmoid tumors are extremely rare, only 12 cases having been reported in the literature. In the 14-year-old girl we describe, a desmoid tumor manifested as an intrathoracic mass. Computed tomography of the chest after administration of intravenous contrast medium showed a large intrathoracic heterogeneous mass and lysis of multiple adjacent vertebral bodies. After incomplete resection of the tumor, T1-weighted magnetic resonance imaging showed residual tumor that produced signal intensity equal to that of skeletal muscle. Intense enhancement after intravenous administration of gadolinium allowed improved delineation of adjacent tissue involvement.